SV650 all the way... the ultimate begginner bike, its cheaper to begin with, cheaper insurance, alot more learner friendly than the gixxers but plenty of bike so once you start learning you won't be bored to death on it, 3 of my tech's in the back are licensed road racers, riding for decades and thats what they all choose to ride still

if you really want a gsxr definetly go with the 600 not the 750, 750 is a good bike but completely over kill considering the 600 is already more than anyone learning needs

so i'd say new or used sv650 or sv650s... or a used gixxer 600, like 97-03 body depending on how much your looking to spend